Hearing loss impairs speech perception and loudness perception, which can have negative effects on academic achievement, cognition, and social functioning. Many aspects of deteriorated hearing performance, such as listening to speech in a complex acoustic background, cannot be explained solely on the basis of peripheral damage. Performance on these tasks is likely affected by neural reorganization or deterioration in the central auditory pathway. The long-term goal of our research program is to investigate how acquired hearing loss affects synaptic organization of the auditory system, how these synaptic changes relate to behavioral changes in hearing, and whether or not the synaptic abnormalities can be recovered or prevented. It is important that we investigate the impact of different forms of hearing loss on the brain to understand variable perceptual deficits and unpredictable outcomes after hearing intervention. This grant will support functional and anatomical investigations in mice with noise-induced hearing damage. Mice will be exposed to moderate noise that has been historically characterized as safe and to moderately loud noise known to cause permanent hearing loss. We will measure behavioral changes in temporal processing and loudness perception and investigate the corresponding changes in structure and organization of neural inputs to specific cell types in the ventral cochlear nucleus. These studies will provide important information for understanding complex hearing deficits and may have implications for improving treatment of hearing loss and for noise trauma prevention guidelines.